He had volunteered for a program that allows Guard members to serve three years on active duty prior to returning to a local Guard unit.

Theinert, who completed the ROTC program at SUNY Albany, is survived by his mother, Chrystyna Kestler; father, James Theinert; and brothers Jim, 22, and Billy, 25.

"His life was based on service; it truly was," Kestler said. "It's such a family tragedy, and a community loss."

His mother described him as selfless, humble, and brave - and a mischievous child, but never malicious.

Friends and family members from Shelter Island, where he graduated from high school, have come together, she said.

"We haven't had to plan a thing. The community has taken care of everything."

She recalled that just before he was deployed to Afghanistan, his brother "Jimbo" asked Theinert if he was frightened to go. Her son, who had wanted to serve his country since he was a little boy, was not scared, she said. He replied that he was "born for it."